Buildings, bridges and other similar constructions traditionally rely upon a steel structure to transmit/transfer internal and external loads to the foundation. The steel framing of a structure includes a plurality of interconnected structural members. Structural steel members are commonly categorized as beams, columns, trusses or bracing, depending upon the manner in which the member is designed to handle, or carry, its load.
Columns, which are disposed in a vertical orientation, are structural members that transmit loading from beams to the foundation. Beams are structural members that are disposed in a horizontal or diagonal orientation within the structure. Bracing are structural members that restrain beams and columns from being displaced/moved from their original location. A structural steel frame consisting of these members is generally designed to carry live, dead, seismic, wind and sometimes cyclic loads. In addition, structural steel frames are often designed to carry loads resulting from snow, ice, or other loads specific to the geographic location, weather conditions, or customized design requirements, such as loads resulting from a blast.
The most common cross-sectional shape of a steel member is an I-shape. The opposing, parallel, horizontal elements of an I-shaped member are commonly referred to in the industry as “flanges.” The single vertical element that extends between and perpendicular to the pair of flanges is commonly referred to as the “web.” Accordingly, it is understood that a member with an I-shape cross-section, commonly referred to in the art simply as an I-beam (wide flange), typically transmits shear forces through its web and bending forces through its flanges. Other common shapes are “L”, “C”, rectangular or circular shapes.
Referring now to FIG. 1, there is shown a simplified block diagram of a well-known prior art system for constructing a building or other similar construction, the system being identified generally by reference numeral 11. As can be seen, system 11 typically includes a plurality of disparate functional groups, or entities, that are responsible for one or more particular tasks in constructing the building. Specifically, as will be explained further in detail below, system 11 commonly includes an architect 13 for creating the overall design of the building, a structural engineer 15 for designing the basic steel structure to handle the load requirements of the building, a general contractor 17 for overseeing the erection of the steel structure of the building at the building site, a fabricator 19 for supplying to general contractor 17 the various steel structure materials to the engineered specifications, a connection engineer 21 for determining a range of suitable connection possibilities between various structural members, and a steel detailer 23 for modeling the steel structure and finalizing the particular means of connection between various structural members based on the load requirements set forth by connection engineer 21.
As the primary step in the construction process, architect 13 draws the design of the structure, including the particular materials to be utilized, and forwards the architectural drawings to structural engineer 13, as depicted by arrow 25. In turn, structural engineer 15 (also commonly referred to in the art as the engineer of record, or EOR,) designs the basic steel structure to handle the various load requirements of the building, including basic design requirements (e.g. unique load requirements due to the inclusion of a pool or balcony) as well as environmental factors (e.g. seismic and wind conditions to be considered). The steel structure designed by structural engineer 15 is then passed to general contractor 17, as represented by arrow 27, for erection of the construction.
However, it should be noted that traditional structural design drawings prepared by structural engineer 15 do not always include a complete set of details relating to how the individual structural members are to be interconnected (or at least do not always fully detail and not always across all conditions) but, more often, are general in nature.
Accordingly, general contractor 17 sends the structural design drawings to fabricator 19, as represented by arrow 29. Fabricator 19, in turn, forwards the structural design drawings to connection engineer 21 to evaluate the requisite load requirements of each point of interconnection between joined structural members, as represented by arrow 31.
As part of the connection engineering process undertaken by engineer 21, each point of interconnection, or joint, between structural members is evaluated based on its various load requirements. In view thereof, connection engineer 21 establishes a sizable number of connection parameters, often organized as a hierarchal list of rules or preferences, as well as a range of acceptable load requirements for each joint that are, in turn, passed to steel detailer 23, as represented by arrow 33.
Notably, connection engineer 21 defines the basic category for each joint, which in turn further defines the connection details. The joint category relates to the way that steel members are to be interconnected. In the art, there are many joint categories, the most common interconnections are (i) beam to beam (i.e., connecting one beam to another, supporting beam), (ii) beam to column flange (i.e., connecting a beam to the flange of a column), and (iii) beam to column web (i.e., connecting a beam to the web of a column). As can be appreciated, the identification of the various joint categories in a structure is significant because each category experiences unique load transfer properties.
Based largely upon the particular joint category selected, connection engineer 21 further determines the specific method of connection (i.e. the connection details) for each joint. The connection details relate to the two or more steel members that are to be permanently joined. Accordingly, the connection details include all relevant parameters relating to the means of interconnection. The most common connective elements used are rectangular steel plates and “L” shaped brackets (plates and angles). The means by which these connective elements are secured to the supporting and the supported members is through the use of connective bolts and weld lines. These are often referred to in the industry as “job standards.” Each job standard form specifies the joint category (e.g. beam to beam, beam to column flange, etc.) and the connection details (e.g. an L-shaped bracket connected to the supporting and supported members) for a corresponding connection in a steel structure.
It should be noted that the bolts or welds used to secure connective elements are often placed/prepared either in the fabrication facility (i.e. in a shop of fabricator 19) or delivered to the construction site and placed/prepared at the time the two or more steel member are joined. For example, a steel connective plate can be welded to one member in the fabricator shop, while the bolts used to connect the plate to the other steel member are installed at the construction site (“field”).
Steel detailer 23, who has a very distinct skill set in relation to connection engineer 21, uses the connection parameters and acceptable load ranges for each joint established by connection engineer 21, generates a three-dimensional model of the steel structure, and uses the job standards developed by connection engineer 21 to connect each joint in the model, commonly referred to in the art as detailing to further define the exact manner in which the individual steel members are to be permanently joined to form the steel structure (e.g. using six bolts of a particular size and grade). That is, the specific connection details for each joint are manually input by detailer 23 into the computer-aided modeling system on a joint-by-joint basis.
As can be appreciated, structural steel connection design requires taking into account a myriad of factors including, but not limited to, (i) the ability to effectively transfer load stresses between members, (ii) the amount of material used to form a suitable connection (e.g. the cost component associated therewith), (iii) the ability to form a joint in the field (i.e. the expected difficulty associated in connecting a joint in a particular manner), (iv) general project requirements imposed by structural engineer 15 and/or steel fabricator 19 (e.g. to meet certain specifications and/or minimize material costs), and (v) the coordinate relationship between structural members (e.g. potential structural obstacles within the connection region).
If the detailing particulars are deemed acceptable by connection engineer 21, as represented by arrow 35, the job standard forms are stamped as approved by connection engineer 21, and are, in turn, sent by connection engineer 21 to structural engineer 15 for approval, as represented by arrow 37. Upon approval by structural engineer 15, as represented by arrow 39, the job standard forms and corresponding electronic files for the steel structure are sent to fabricator 19, as represented by arrow 41. Fabricator 19 is then able to manufacture and mark all the necessary components for the steel structure to the requested specifications and, in turn, deliver the components to the general contractor 17 at the designated site for erection of the construct, as represented by arrow 43.
As can be appreciated, the above-described steel structure construction process has been found to suffer from a number of notable shortcomings.
As a first shortcoming, the aforementioned process relies upon a large number of disparate entities that are required to undertake separate, yet complementary, sets of tasks. At the same time, it should be noted that the connection engineering and detailing process undertaken by connection engineer 21 and steel detailer 23 are often largely influenced by basic requirements set forth by structural engineer 15 as well as material preferences established of fabricator 19 (e.g. if fabricator 19 can obtain or construct a particular component at a reduced cost). However, because each entity operates in a largely autonomous nature and has limited means to communicate with other entities in system 11, the overall construction process is rendered largely inefficient.
As a second shortcoming, the aforementioned process of engineering and detailing a joint includes two separate steps that are undertaken by two separate entities. Specifically, the aforementioned joint connection process requires a connection engineer 21 to first manually engineer a range of suitable connection parameters for each joint. Thereafter, a steel detailer 23 is required to manually input the engineered connection parameters into a computer modeling system, thereby increasing costs, restricting productivity, and potentially impacting the quality/accuracy of the connection.
As a third shortcoming, because support structures can include hundreds to thousands of joints, the manual component associated with engineering and detailing each joint renders the process rather time-consuming in nature.
As a fourth shortcoming, the utilization of load ranges by connection engineer 21 during the engineering step of the structural detailing process creates a significant degree of engineering uncertainty and, as such, requires the review of every connected condition input by detailer 23 to ensure compliance. Furthermore, detailing that results in load conditions that fall outside of the defined range require individualized redesign by engineer 21, thereby further lengthening the overall process.